1. Field of the Invention
The present invention deals with a filling thread insertion or shooting needle for a ribbon weaving machine as well as a ribbon weaving machine itself equipped with such a filling thread insertion needle.
Various embodiment forms of filling thread insertion needles are used in ribbon weaving machines.
2. Description of the Prior Art
In the group of embodiment forms of filling thread insertion needles (EP 0 121 648 B1, GB 1 424 301, GB 2 146 665 A) a hook exists for gripping the filling thread to be inserted and a thread guide is provided for additional filling threads. The thread guiding is accomplished through a slot, which extends essentially across the length of the needle. This slot can be configured within the needle or can be formed by the needle body and a second member connected therewith. These embodiment forms have the following disadvantages in common: that the guidance is disposed either above or below the needle body and consequently the filling threads, which do not have to be inserted cannot form a shed and are carried along loosely similar to warp threads and also that a filling thread, which is not inserted over a larger distance, floats and becomes visible at the edge of the fabric. This can indeed be partially prevented in that blind fillers are inserted, which is disadvantageous, since the overall productivity is thereby reduced, meaning the weaving output is lower and the thread consumption is greater. In addition such blind fillers can impair the appearance of the fabric, in particular because loose dark figure or fancy threads appear as being translucent through light color weaves.
In another group of embodiment forms the filling thread insertion or shooting needles have only a hook at the needle tip, which is configured on the needle at the bottom or the top. A guidance has not been provided. In these embodiment forms the shedding motion of the non-inserted filling threads is possible. In this case it is disadvantageous that the filling thread can be inserted only on one side, which excludes the so-called pic-pic, and that a special laying-in device is required, whereby the weaving speed is reduced because of the extremely rapid laying-in and picking-out motion.
Finally filling thread insertion or shooting needles are known (CH 16 654 A5), which comprise a fork-shaped recess at the needle tip for gripping the filling thread to be inserted. With this filling thread insertion needle any desired filling change is possible wherein however the following disadvantages have to be accepted:
1. Sticking and crossed warp threads, which get into the effective range of the fork, are carried along as filling threads. Weaving errors and warp thread breaks consequently occur. PA1 2. The inserted filling thread is not pulled back by the needle since the fork is open towards the tip of the needle. Due to this a higher filling thread tension must be provided which tends to increase the filling thread breaks. PA1 of any random filling change pic a pic, meaning from above and below the needle body; PA1 to tie the non-inserted filling threads such as warp threads into the edge of the weave or tissue, thus making them invisible; PA1 to control the reading-in of the filling thread and the shedding motion by a conventional Jacquard apparatus; PA1 to use a color control device directly as a shedding motion device without using any special motion sequence; PA1 to tension of the lastly inserted filling thread and to produce a fine impeccably tensioned stitch edge.
Both above phenomena have a disadvantageous or negative effect upon the productivity of the ribbon weaving machine.